Volume 11, Issue 3 (2026)
SJMR 2026, 11(3): 139-149 |
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Nateghi M R, Mohammadian H. Causes of Bleeding During the First Trimester of Pregnancy (Review Article). , SJMR. 2026; 11 (3) : 6
URL: http://saremjrm.com/article-1-410-en.html
URL: http://saremjrm.com/article-1-410-en.html
1- Sarem Gynecology, Obstetrics and Infertility Research Center, Sarem Women’s Hospital, Iran University of Medical Science (IUMS), Tehran, Iran. & Sarem Cell Research Center (SCRC), Sarem Women’s Hospital, Tehran, Iran.
2- Sarem Gynecology, Obstetrics and Infertility Research Center, Sarem Women’s Hospital, Iran University of Medical Science (IUMS), Tehran, Iran.
2- Sarem Gynecology, Obstetrics and Infertility Research Center, Sarem Women’s Hospital, Iran University of Medical Science (IUMS), Tehran, Iran.
Abstract: (6 Views)
Vaginal bleeding during the first trimester of pregnancy is one of the most common obstetric complications, affecting approximately one-quarter of pregnant women. This condition can range from mild, benign spotting to severe, life-threatening hemorrhage and serves as a significant indicator for adverse maternal and fetal outcomes—such as spontaneous abortion, preterm birth, low birth weight, preterm premature rupture of membranes (PPROM), placental abruption, placenta previa, and stillbirth.
The causes of first-trimester bleeding are broadly categorized into obstetric and non-obstetric etiologies. Among obstetric causes, threatened miscarriage is the most frequent diagnosis; other significant causes include early pregnancy loss, ectopic pregnancy, and gestational trophoblastic disease (GTD). Non-obstetric causes include genital tract infections, cervical polyps, cervical lesions or ulcers, and subchorionic hematomas. Subchorionic hematoma is a common sonographic finding; when large, it is associated with an increased risk of miscarriage and other pregnancy complications.
Diagnosing the cause of bleeding requires a thorough clinical evaluation, laboratory testing, and diagnostic imaging. Transvaginal ultrasound, the imaging modality of choice, plays a pivotal role in the differential diagnosis, measurement of serum β-hCG and progesterone levels can assist in distinguishing between normal and abnormal pregnancies. Several risk factors are associated with an increased likelihood of first-trimester bleeding, including maternal age (over 35 or under 20), recurrent miscarriage, smoking and alcohol consumption, obesity, excessive caffeine intake, diabetes, hypertension, thyroid disorders, uterine abnormalities (such as fibroids or a uterine septum), fetal aneuploidy, infections, the use of assisted reproductive technologies, psychosocial factors, and domestic violence.
Since some causes of bleeding (such as fetal chromosomal abnormalities) are beyond the mother's control, it is not possible to prevent every instance; however, identifying and addressing modifiable risk factors can help reduce the likelihood of spontaneous miscarriage and certain causes of bleeding. Key preventive strategies include lifestyle modifications (e.g., quitting smoking, weight management, and reducing caffeine intake), the management of underlying medical conditions (such as diabetes and thyroid disorders), the assessment of structural uterine abnormalities, preconception care, and early monitoring. Transvaginal ultrasound in early pregnancy, along with serial monitoring in selected women, can facilitate the early detection of abnormal pregnancies and help mitigate severe outcomes. For women experiencing a threatened miscarriage (particularly those with recurrent miscarriag miscarriage) progesterone therapy may increase the likelihood of a live birth; however, its routine administration is not recommended for all women. Furthermore, there is insufficient evidence to support the use of bed rest or the routine administration of tranexamic acid for the prevention of miscarriage or bleeding. The appropriate approach for women experiencing first-trimester bleeding should be based on diagnosing the cause of the bleeding, assessing the status of both the mother and the fetus, identifying modifiable risk factors, and providing targeted treatment for the underlying cause.
The causes of first-trimester bleeding are broadly categorized into obstetric and non-obstetric etiologies. Among obstetric causes, threatened miscarriage is the most frequent diagnosis; other significant causes include early pregnancy loss, ectopic pregnancy, and gestational trophoblastic disease (GTD). Non-obstetric causes include genital tract infections, cervical polyps, cervical lesions or ulcers, and subchorionic hematomas. Subchorionic hematoma is a common sonographic finding; when large, it is associated with an increased risk of miscarriage and other pregnancy complications.
Diagnosing the cause of bleeding requires a thorough clinical evaluation, laboratory testing, and diagnostic imaging. Transvaginal ultrasound, the imaging modality of choice, plays a pivotal role in the differential diagnosis, measurement of serum β-hCG and progesterone levels can assist in distinguishing between normal and abnormal pregnancies. Several risk factors are associated with an increased likelihood of first-trimester bleeding, including maternal age (over 35 or under 20), recurrent miscarriage, smoking and alcohol consumption, obesity, excessive caffeine intake, diabetes, hypertension, thyroid disorders, uterine abnormalities (such as fibroids or a uterine septum), fetal aneuploidy, infections, the use of assisted reproductive technologies, psychosocial factors, and domestic violence.
Since some causes of bleeding (such as fetal chromosomal abnormalities) are beyond the mother's control, it is not possible to prevent every instance; however, identifying and addressing modifiable risk factors can help reduce the likelihood of spontaneous miscarriage and certain causes of bleeding. Key preventive strategies include lifestyle modifications (e.g., quitting smoking, weight management, and reducing caffeine intake), the management of underlying medical conditions (such as diabetes and thyroid disorders), the assessment of structural uterine abnormalities, preconception care, and early monitoring. Transvaginal ultrasound in early pregnancy, along with serial monitoring in selected women, can facilitate the early detection of abnormal pregnancies and help mitigate severe outcomes. For women experiencing a threatened miscarriage (particularly those with recurrent miscarriag miscarriage) progesterone therapy may increase the likelihood of a live birth; however, its routine administration is not recommended for all women. Furthermore, there is insufficient evidence to support the use of bed rest or the routine administration of tranexamic acid for the prevention of miscarriage or bleeding. The appropriate approach for women experiencing first-trimester bleeding should be based on diagnosing the cause of the bleeding, assessing the status of both the mother and the fetus, identifying modifiable risk factors, and providing targeted treatment for the underlying cause.
Article number: 6
Keywords: First-trimester bleeding, threatened miscarriage, ectopic pregnancy, gestational trophoblastic disease, subchorionic hematoma, risk factors, prevention.
Article Type: Analytical Review |
Subject:
Pregnancy Care
Received: 2026/10/2 | Accepted: 2026/10/22 | Published: 2026/11/12
Received: 2026/10/2 | Accepted: 2026/10/22 | Published: 2026/11/12
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